<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Media Queries PC First Demo</title>
    <style>
        body {
            padding: 0;
            margin: 0;
            font-size: 3rem;

            min-width: 320px;
            box-sizing: border-box;
        }
        .container {
            display: grid;
            grid-template-columns: 1fr 1fr 1fr 1fr;
            grid-template-rows: 100px;
            grid-auto-rows: 100px;
            width: 100%;
            gap: 10px;
        }
        .container > div {
            background-color: aqua;
        }

        @media (max-width: 1920px) {
            .container {
                grid-template-columns: 1fr 1fr 1fr;
            }
        }
        @media (max-width: 1024px) {
            .container {
                grid-template-columns: 1fr 1fr;
            }
        }
        @media (max-width: 480px) {
            .container {
                grid-template-columns: 1fr;
            }
        }
    </style>
</head>
<body>
    <div class="container">
        <div class="child">1</div>
        <div class="child">2</div>
        <div class="child">3</div>
        <div class="child">4</div>
        <div class="child">5</div>
        <div class="child">6</div>
        <div class="child">7</div>
        <div class="child">8</div>
        <div class="child">9</div>
        <div class="child">10</div>
        <div class="child">11</div>
        <div class="child">12</div>
        <div class="child">13</div>
        <div class="child">14</div>
        <div class="child">15</div>
        <div class="child">16</div>
        <div class="child">17</div>
        <div class="child">18</div>
        <div class="child">19</div>
        <div class="child">20</div>
    </div>
</body>
</html>